Gun sight



32a-252. w 7,213,578 5R SePf- 3, 1940. B. F. DALLE MOLLE 2,213,678

`GUN SIGHT Filed Jan. 29, 1940 2 Sheets-Sheet 1 lTLvET-Ltm" Eeneict RDLLUE MURE EEN AQ. Att E11/'maya 33. GEUMETWCL Nliuwltwm, 1 P R mmm Sept. 35,1940. B. F. DALLE MOLLE 2,213,673'

GUN SIGHT I med Jan. 29, 1940 2 sheets-sheet z lTLvE mtu 1^ EJEVLE '11:1'. Il Ulla Mull E Att nvmeyi Patented Sept. 3, 1940 UNITED STATES @earch iocui PATENT OFFICE 5 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a sight for guns and more particularly to a sight for antiaircraft or similar guns.

The principal object of the invention is to provide a relatively simple and compact sight that may be expeditiously employed in calculating the lateral and vertical leads at which a gun must be trained with respect to a moving aerial or similar target in order to ensure placing the cone of fire emanating from the gun on the target.

A further object of the invention is to employ a rear sight of the folding leaf type having a range or time of flight scale provided thereon in combination with a range finding or determining device displaceable along the scale, in the folded position of the leaf element, to set a sighting element, such as a member bearing a peep aperture, at the range of the target to the scale on the leaf element whereupon the rear sight will be properly set in range when the leaf element is erected.

A still further object of the invention is to provide a front sight that is symmetrically split and so arranged that the split portions may be simultaneously laterally displaced through equal angles independently of the gun in relative opposite directions to and from their normal full sight forming position overlying the axis of the bore for measuring the angular lateral rate of a moving target.

The specic nature of the invention as well as other objects and advantages thereofv will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a plan View of a gun provided with the sighting system of this invention and shows the front sight in its normal full sight forming position and the rear sight with its leaf in the folded position;

Fig. 2 is a plan view showing the front sight in displaced position and the rear sight leaf erected;

Fig. 3 is a rear elevation of the rear sight with the leaf element in erected position;

Fig. 4 is a rear elevation of the rear sight with the leaf element in folded position;

Fig. 5 is a sectional View to enlarged scale taken on the line 5--5 of Fig. 1;

Fig. 6 is a sectional view to enlarged scale taken on the line 6 6 of Fig. 1.

Referring now to the drawings by reference characters there is shown in Fig. 1 a gun G provided with a sighting system comprising the front sight It and rear sight Il.

The rear sight II includes a base I2 suitably affixed to the gun G and a rear sight leaf I3 hinged by the joint pin I4 to the base I2, as indicated in Fig. 3, for pivotal movement from its folded position as shown in Fig. 4 to its erected position shown in Fig. 3. As in conventional sight leafs, the leaf I3 may be formed to have two branches I5 and I6 which are undercut as indicated at II for the purpose of imparting lateral movement to a drift slide I8 as it is moved up or down on the leaf, thus automatically correcting for drift of a projectile fired from the gun, as is well understood in the art.

The drift slide I8 may conveniently be retained in the undercuts I'I by a slide member I9 adjustably secured to the leaf I3 for sliding movement to any position therealong, and is laterally movable with respect to the slide member as the latter is moved along the leaf to permit the undercuts to automatically position the drift slide to compensate for drift. One or more peep apertures 2li are formed in the drift slide so that the rear sight thus far described may be used, in its erected position, as a conventional sight in training the gun on relatively slow moving or stationary targets, by simply aligning the peep aperture with the graduation on the range or time of flight scale 2l corresponding to the range of the target. The scale 2| may be engraved or otherwise suitably affixed on the leaf I3 in any desirable position, but for a purpose made clear hereinafter it is preferred to engrave the scale 2l on the outer edge of the branch I5 of the leaf I3 as indicated in Fig. 3.

A range finding or determining device operating upon the principle that the angle Subtended by an object of given dimension transverse to the line of observation at a given point, is proportional to the range of the object from that point, is combined with the rear sight above described to automatically set a sight of the devices in range or time of flight during the operation o-f determining the range of any target from the gun.

The range finding device comprises a rectangular range plate 22 of substantially the same transverse and longitudinal dimensions as the sight leaf I3 secured to the latter on the side remote from drift slide I8, and is formed With an elongated opening 23 of general triangular shape disposed between the branches i5 and I6 of sight leaf I3 with the base of the opening adjacent the joint pin I4. A track 2li is secured to the range plate on either side of opening 23 in parallelism with the adjacent side of the opening, as by the standards or ribs 25 and serve to guide the movement of substantially identical range sights 26 as they are moved longitudinally of the range plate. Each range sight 26 is formed with a base portion 21 and upright sighting edge portion 28 which is arranged in normal relation with respect to the base and depends as a shank therebelow where it is terminated in a guide sleeve 29 adapted to be sleeved over a track 24. To eect conjoint movement of the sights 26 longitudinally of the range plate and consequent adjustment of the lateral spacing of the sighting edges 28 thereof, a sight bar 3B having a transverse rectangular opening 3l therein is secured to the slide member i9 below the peep aperture 2li and the Shanks of the sights 26 are disposed in the opening 3| with the bases 2l engaging the adjacent surface of the bar whereby they may freely move to and from each other as they are moved longitudinally of the tracks 24 by the slide I9 and bar 3E! secured to the slide. Helical tension springs 32 or similar resilient devices are secured to each of the sights 26 and sight bar 3D so as to ensure that the sights will always be maintained with their depending Shanks in engagement with the longitudinal edges of opening 23 and with the sighting edges 28 in planes parallel with the axis of the bcre of the gun. While in the embodiment of the invention herein shown the sight bar Bil has been disclosed as attached to and movable by the slide member I9 it will be understood that such disclosure is merely by way of illustration and not of limitation, for if desired, the sight bar Si! may be substituted for the slide i9 by obvious mechanical expedients. In the form shown the sight bar 3i) is formed with a peep aperture 33 so related to the scale 2i and sighting elements 2E that when the latter are properly sighted on a target the peep aperture will be aligned with the graduation on scale 2l corresponding with the range or time of flight of the target from the gun.

The shape of opening 23 in the range plate 22 is determined by the ballistics of the gun and average front of enemy target, against which the gun is intended to be employed, as seen by the gunner or other observer at the gun for the purpose of description of which 30 feet may be assumed although this is not to be regarded as limitative in nature since any value may be employed. The base of the opening is several inches forwardly of the point of observation or gunners eye and is the chord subtended by the same angle at the point of observation or gunners eye which subtends a target at the minimum range for which the sight is designed. This chord, which is coincident with the base of the opening 23, is so located in the range plate that when the sight leaf i3 erected with the peep aperture 33 aligned with the chord and the gun trained by means of the peep aperture and front sight at a target of minimum range of the sight that the gun will be properiy pointed at the target with respect to the trajectory of a projectile fired therefrom. The apex portion of opening 23 includes a chord which is subtended by the same angle at the point of observation or gunners eye which subtends the target at the maximum range of the gun, or the limiting angle of resolution of the average eye, as the case may be, and is so located in the range plate that when the peep aperture 33 is aligned therewith with the leaf i3 in erected position and the gun trained by the peep aperture and front sight at a target of maximum range that the gun will be properly pointed at the target in range or time of flight with respect to the trajectory of a projectile iired therefrom. The base and apex portion chords of the opening are joined by straight sides to define the opening 23 as shown, and as is obvious from inspection, any chord joining the straight edge sides of the opening will be in proportion to the range of a target, subtended by the same angle at the point of observation or gunners eye which subtends the chord, in accordance with the simple geometric proposition that in two similar triangles homologous sides are proportional. Also any chord falling intermediate the base and apex portion chords will vary in ratio with respect to these chords that is proportional to the maximum and minimum ranges; from whence, ranges intermediate the maximum and minimum ranges may be simply determined by moving the sights 26 up or down the range plate until the distance between them coincides with a chord intermediate the base and apex portion chords. that is subtended by the same angle at the point of observation or gunners eye which subtends the target. Any particular chord intermediate the base and apex portion chords of the opening 23 may be established by moving the slide l2 and sights 26 up or down the range plate 22 until the space between the edges 28 of the sights 26 is subtended by the same angle which subtends the target at the point of observation or gunners eye. The range or time of flight corresponding to the setting of the sights 26 may be read directly from the scale 2| opposite an appropriate index on the sight bar 3i). As more particularly shown in Fig. 3 at 313 the lower portion of the opening 23 is extended at the same chord width for a short space to facilitate positioning the sights 26 at the minimum range.

The front sight IB comprises a pair of identical sight arms 35 arranged to overlie the axis of the bore of the gun in symmetrical relation and extend from a point adjacent the muzzle of the gun rearwardly to any suitable location in the proximity of the rear sight Il Where they are secured to intermeshing gears 36 suitably journaled on the gun at 3i for rotation in relatively opposed directions. For rotating the gears 36 and sight arms a worm wheel 38 is secured on one of the journal pins of the journals Si' and is in meshing relation with a Worm 3s rotatable by the shaft iii and knurled knob 4l or other suitable hand grasp. A front sighting element including symmetrically formed sight blades 62 secured one to the forward end of each sight arm in such manner as to form a full sight overlying the axis of the bore is provided.

In the operation of a gun, against a moving target, with the sighting system of this invention the gunner places the rear sight leaf I3 in its folded position and observes the target through the range sights 26, and if the space between these sights does not subtend the same angle as the targetA he adjusts the spacing thereof by moving the slide member l up or down on the leaf i3 until such spacing does coincide with a chord between the sides of opening 23 in range plate 22 that subtends the same angle as the pli.

earch o target. When the sights 26 have been properly adjusted he signies such fact to his assistant who immediately locks the gun against traversing and simultaneously therewith notes the time of flight indicated on the time of flight scale 2| abut when the arms overlie the axis of the bore to form a full sight.

2. In a sighting system a front sight comprising in combination, a pair of sight arms adapted 5 to overlie the axis of the bore of a gun in paralby the index on bar 30 and initiates operation lel relation, intermeshing gears secured to the of a stop watch. In sequence following the derear ends of the arms, means for journaling said termination of the range by the gunner and the gears to a gun, means to rotate one of said locking of the gun against traversing movement gears whereby the arms may be angularly disby his assistant the gunner continues to track placed in opposite directions relative to the axis the target through the opening'. between the of the bore of a gun and symmetrical sight sights 26 and the appropriate sight blade 42 on blades secured to the front ends of the arms and the corresponding sight arm 35 by rotating the adapted to abut in the parallel relation of the shaft 40 through the knob 4I. At the expiraarms to form a full sight overlying the axis of tion of the time of flight indicated on the scale the bore. V

2| and determined by the gunners eSSiStenll 3. In a sighting system a rear sight comprising With the aid 0f his Stop Wath, the gunner Will in combination, a leaf, a pair of separate tracks Cease t0 Week the target by mOVemeDl 0f the secured to the leaf in converging relation away front Sight has now been displaced to e position from the base of the leaf, a sight bar secured to go unlock the gun for traversing movement. The the leaf for longitudinally sliding movement front sight has now been displaced to a position therealong, a range sight secured to each track similar to the one illustrated in Fig. 2 in which and means for conjointly moving the sight bar position the sight blades 42 indicate the lateral and range sights longitudinally of the leaf; rate of travel during the time of night of a prowhereby the longitudinally positioning of the jectile fired from the gun in traversing the dissight bar and range sights may be made to cortance to the target. The gunner immediately respond with the range or time of flight of a following expiration of the time of flight meastarget observed through the range sights. ured by his assistant raises the rear sight leaf 4. In a sighting system a rear sight comprising I3 and trains the gun on the target by means of in combination, a foldable leaf, a range plate so the peep aperture 33 and front sight blade 42 provided with an elongated opening of general remote from the one he tracked the target with triangular shape secured to the leaf with the base which will point the gun with the proper lead of said opening adjacent the base of the leaf, a with respect to the target. In the case of fast track secured to the range plate in parallelism moving targets the initial leads calculated as with each elongated side of the opening, a sight above explained will serve as a basis for corbar having a peep aperture and transverse open- 35 rections to be applied by the gunner in pointing ing secured to the leaf for longitudinal sliding the gun at the target under subsequent condimovement thereof, a range sight provided with tions of range and angular travel. For stationa shank portion secured to each track and havary targets the range finding device may be ing its shank portion engaging the elongated employed in connection with a conventional adjacent side of said range plate opening and rear sight as will appear from the above deprotruding through the opening in said sight scription. bar, means for maintaining said shank portions Having now described the invention in its in engagement with the sides of the range plate present preferred form what I claim is: opening, and means for moving said sight bar 1. In a sighting system a front sight comprislongitudinally of the leaf.

ing in combination, a pair of sight arms, means 5. The structure of claim 4 wherein said range for pivotally mounting the arms at their rear sights are secured to the gun and each comprises ends to a gun for opposed angular movement a sighting edge disposed in a plane parallel with about the pivots to and from a position overlying the vertical plane of the axis of the bore of gun the axis of the bore of said gun, means for and base portions joining said sighting edges ensimultaneously pivoting said arms about their pivots in opposed angular directions of equal magnitude and symmetrical sight blades secured to the forward ends of said arms and adapted to gaging the sight bar outwardly of said sighting edges.

BENEDICT F. DALLE MOLLE. 

